The present invention relates to an optical apparatus accessory, such as an interchangeable lens, which is detachably attachable to an optical apparatus such as a camera.
Camera systems each including an interchangeable lens and a camera are configured such that multiple terminal pins provided in a mount portion of the camera make contact with multiple terminal faces provided in a mount portion of the interchangeable lens. Contact of each terminal pin with each terminal face corresponding thereto (that is, contact of paired terminal pin and face) among the multiple terminal pins and faces establishes electric connection between the camera and the interchangeable lens to supply power from the camera to the interchangeable lens and to send and receive various signals and information between the camera and the interchangeable lens.
The terminal pins and the terminal faces are arranged such that they are mutually slid by relative rotation of the camera and the interchangeable lens in order to attach their mounts to each other (couple them with each other by a bayonet coupling) and thereby the paired terminal pin and face make contact with each other in an attachment completed state.
However, in order to cause the terminal pin to make press contact with the terminal face, the terminal pin is held protrudedly and retractably in its axial direction and is biased with a spring in its protruding direction. Therefore, the terminal pin is not only movable in its axial direction but also allowed its displacement in its radial direction. In addition, repetition of attachment and detachment of the camera and interchangeable lens causes bend of the terminal pin or increase in diameter of a tip of the terminal pin due to abrasion. In these cases, in the attachment completed state, a contact failure occurs because the terminal pin does not make contact with the terminal face originally corresponding thereto, or a short circuit occurs because the terminal pin makes contact not only with the terminal face originally corresponding thereto but also with another terminal pin adjacent the originally corresponding terminal face. Thus, it is necessary to make a height of an electric insulation portion provided between the mutually adjacent terminal faces higher than that of the terminal face for preventing the terminal pin from moving onto the electric insulation portion or to increase a width of the electric insulation portion for preventing the terminal pin from simultaneously making contact with the mutually adjacent terminal faces.
Japanese Laid-Open No. 02-103522 discloses a configuration in which a height of one of two power supply terminals (terminal pins and terminal faces) included in each of multiple terminal pins provided in a camera and multiple terminal faces provided in an interchangeable lens is different from that of the other power supply terminal, that is, a configuration including a height difference. In this configuration, the one power supply terminal does not make contact with the other power supply terminal during relative rotation of the camera and interchangeable lens for attachment thereof, so that abrasion thereof is suppressed.
Furthermore, Japanese Laid-Open No. 2007-101656 discloses a configuration in which an attachment detection terminal (terminal pin or terminal face) for detecting attachment of an interchangeable lens to a camera is provided in each of multiple terminal pins provided in the camera and multiple terminal faces provided in the interchangeable lens and in which a distance between the attachment detection terminal and a terminal adjacent thereto with an electric insulation portion provided therebetween is set larger than that between other terminals.
However, the configuration disclosed in Japanese Laid-Open No. 02-103522 requires, as the height difference, a height that can prevent the one power supply terminal from making contact with the other power supply terminal during the relative rotation of the interchangeable lens, which increases a size of a terminal portion including the terminals in its height direction.
In addition, the configuration disclosed in Japanese Laid-Open No. 2007-101656 increases the distance between the attachment detection terminal and the terminal adjacent thereto, which increases a length of a terminal portion including the terminals in its terminal arrangement direction (that is, in a direction of the relative rotation of the interchangeable lens and camera).